The present invention relates to a sensor device for detecting a shifting position of a vehicle transmission, to a vehicle transmission and to a method for detecting a shifting position of a vehicle transmission.
Inductive sensors, e.g. moving coils, planar coils and the like are frequently used for detecting a shifting position of a vehicle transmission. Here, in automotive applications in particular, a permanent magnet is normally disposed in a transmission chamber or oil chamber and a sensor element is disposed separately from the oil chamber.
It is an object of the present invention to provide an improved sensor device for detecting a shifting position of a vehicle transmission, an improved vehicle transmission and an improved method for detecting a shifting position of a vehicle transmission.
This object is achieved by a sensor device for detecting a shifting position of a vehicle transmission, a vehicle transmission and a method for detecting a shifting position of a vehicle transmission according to embodiments of the invention.
According to embodiments of the present invention, a transducer element of a sensor for detecting a shifting position of the vehicle transmission can be sealed, separated or encapsulated relative to a transmission chamber containing lubricant, also referred to as an oil chamber. In this case, the transducer element is, in particular, disposed on a component that is designed for transferring a displacement of a transmission element that is dependent on a change in the shifting position to the transducer element.
As a result of the separation or encapsulation of the transducer element relative to the actual transmission chamber of the vehicle transmission, a risk of fouling of the transducer element, for example by swarf from transmission elements in the transmission chamber or oil chamber, can be avoided or excluded. In particular, fouling of the transducer element by ferritic particles of transmission elements in the transmission chamber or oil chamber can be prevented. As a result, the detection accuracy as well as the longevity of a sensor device for detecting a shifting position of a vehicle transmission can be improved.
As a result, a sensor or a sensor device with a transducer element, for example in the form of a permanent magnet, can be used for a transmission control module. The transducer element can be disposed in a separate chamber that is sealed off from the transmission chamber. A detection device of the sensor can for example be disposed separately from the transmission chamber. The detection device and the transducer element can be disposed spaced apart from each other. As a result of the arrangement of the transducer element in a separate sealed chamber, it can be reliably prevented that a magnetic transducer element attracts, for example, ferritic particles from the transmission chamber and unintentionally acts as a swarf collector. Consequently, a change of a sensor signal caused by fouling such that a displacement position would be detected incorrectly can be prevented over the lifetime of the sensor device.
A sensor device for detecting a shifting position of a vehicle transmission comprising a transmission chamber in which transmission elements are disposed has the following features:
(a) a bar element extending from the transmission chamber into an adjoining chamber that is sealed off from the transmission chamber and that is disposed so as to be displaceable depending on the shifting position, wherein the bar element comprises an interface disposed in the transmission chamber for coupling the bar element to a transmission element that is positioned depending on the shifting position and that comprises an accommodating segment that is disposed in the adjoining chamber;
(b) a transducer element that is mounted on the accommodating segment of the bar element; and
(c) a detection device for detecting a position of the transducer element that is dependent on the shifting position or a displacement of the transducer element that is dependent on a change of the shifting position.
The vehicle transmission can be a manual transmission, a direct shift gearbox, an automated manual transmission (AMT) or an automatic transmission (AT). The vehicle transmission can be provided for a vehicle that can be a motor vehicle, such as for example an automobile or a commercial vehicle, a rail vehicle or a waterborne vessel. The transmission chamber of the vehicle transmission can be at least partly enclosed by a transmission housing. The transmission elements as well as at least one lubricant can be disposed in the transmission chamber. The transmission elements can be transmission shafts, gearwheels, pinions, a selector shaft, a selector fork and the like. The transmission chamber can be fouled by freely moving swarf. The shifting position or a shift state of the vehicle transmission can correspond to an engaged gear or an engaged drive position of the vehicle. The sensor device can be based on a contactless detection principle. The adjoining chamber can be sealed off from the transmission chamber and separated relative to the surroundings of the vehicle transmission or connected thereto by means of an opening. As a result, the adjoining chamber can be kept free of the swarf present in the transmission chamber. The bar element can be a rod, piston rod or similar. The bar element can be made of a non-magnetic material. The interface can be disposed on a first end of the bar element and the accommodating segment can be disposed on a second end of the bar element. The interface of the bar element remains in the transmission chamber during a displacement of the bar that is dependent on the shifting position. The accommodating segment of the bar element remains in the adjoining chamber during a displacement of the bar element that is dependent on the shifting position. The interface can comprise an attachment segment for attaching a connecting element to the transmission element that is positioned depending on the shifting position. The accommodating segment can be designed to accommodate the transducer element. By disposing the transducer element within the adjoining chamber, the transducer element is protected against fouling by the swarf present in the transmission chamber, which could be attracted by the transducer element. The detection device can be disposed outside the transmission chamber of the vehicle transmission.
At least one sealing element can also be provided for fluid-tight and/or particle-tight sealing of the adjoining chamber off from the transmission chamber. In this case the bar element can be fed through the at least one sealing element. In particular, the at least one sealing element can be designed to seal an opening of the adjoining chamber to the transmission chamber, for example against swarf. The at least one sealing element can comprise a sealing sleeve, a sealing ring or similar. The at least one sealing element can be designed to enable a displacement of the bar element that is dependent on a change of the shifting position, wherein a sealing effect of the at least one sealing element is maintained. Such an embodiment gives the advantage that the adjoining chamber can be reliably sealed off from the transmission chamber while preserving mobility of the bar element.
Furthermore, at least one guide element can be provided, which is disposed in the adjoining chamber at least partly around the bar element. The at least one guide element can be designed to guide the bar element in the adjoining chamber along an axis of motion of the bar element during a displacement of the bar element that is dependent on a change of the shifting position. The at least one guide element can be in the form of or act as a slide bearing. Such an embodiment gives the advantage that tilting of the bar element with the transducer element or measurement element relative to the axis of motion can be prevented because of the at least one guide element. In other words, the distance of the axis of motion from the detection device can be essentially held constant, so that a change of a sensor signal caused by such tilting or a change of distance can be prevented.
In this case the detection device can be designed to detect a direction of motion of the transducer element along an axis of motion of the bar element that is dependent on a change of the shifting position during a displacement of the transducer element mounted on the bar element that is dependent on a change of the shifting position. Such an embodiment gives the advantage that compensation of manufacturing and/or assembly tolerances can be achieved during the exclusive measurement of a direction of motion.
According to one embodiment, the detection device can comprise a sensor based on a magnetic principle and the transducer element can comprise a magnet or a magnetisable material. In this case the detection device or the sensor device can comprise a magnetic field sensor, a Hall sensor or similar. The transducer element can, for example, be implemented as a permanent magnet or as a unit to be magnetized. Such an embodiment gives the advantage that a position and/or displacement of the transducer element can be determined contactlessly for shifting position detection, even if, for example, the detecting device is disposed so as to be separated from the transducer element by an air gap, a housing wall or similar.
In particular, the bar element can be made of aluminum or plastic. The bar element can comprise a non-magnetic material. Such an embodiment gives the advantage that a position determination or displacement determination of the transducer element by the detection device is not interfered with or adversely affected.
A vehicle transmission comprising a transmission chamber in which transmission elements are disposed also has the following features:
(a) a selector fork that is disposed in the transmission chamber and that is designed to shift at least one transmission element;
(b) a selector shaft that is disposed in the transmission chamber and that is designed to displace the selector fork depending on a shifting position of the vehicle transmission; and
(c) a version of the aforementioned sensor device for detecting a shifting position of the vehicle transmission, wherein the interface of the bar element of the sensor device is mechanically coupled to the selector fork by means of at least one connecting element.
The selector fork can represent the transmission element of the vehicle transmission that is positioned depending on the shifting position. The selector shaft can be displaced translationally depending on the shifting position. The selector shaft can be designed to displace the selector fork along an axis of the selector shaft depending on the shifting position. A translational displacement of the selector fork that is dependent on the shifting position can be transferred into a translational displacement of the bar element by means of the at least one connecting element. A shifting position or a shift state of the vehicle transmission can be advantageously detected by way of a version of the aforementioned sensor device.
In this case the at least one connecting element can be designed to transfer a displacement that is dependent on a change of the shifting position of the selector fork to the bar element of the sensor device. By use of the at least one connecting element, a translational displacement that is dependent on the shifting position of the selector fork can be transferred into a translational displacement of the bar element. Such an embodiment gives the advantage that the shifting position can be reliably detected by the sensor device.
According to one embodiment, the at least one connecting element can comprise a connecting rod, whose first end is mechanically coupled to the interface of the bar element and whose second end comprises a ball segment or is connected to or a ball element. Here, the ball segment or the ball element can be designed to be mechanically connected to the selector fork. In this case the ball segment or the ball element can be displaceably connected to the selector fork. Such an embodiment gives the advantage that compensation of tolerances and measurement of a direction of motion that is dependent on a change of the shifting state are enabled by a position transfer by way of guide elements of the sensor device as well as the at least one connecting element with a ball segment or a ball element.
A method for detecting a shifting position of a vehicle transmission, wherein the vehicle transmission comprises a transmission chamber in which transmission elements are disposed, comprises the following acts:
(a) transferring a displacement that is dependent on a change of the shifting position of a transmission element that is positioned depending on the shifting position and that is disposed in the transmission chamber to a bar element, wherein the bar element extends from the transmission chamber into an adjoining chamber that is sealed off from the transmission chamber and the bar element is displaceable depending on the shifting position, wherein the bar element comprises an interface that is disposed in the transmission chamber for coupling the bar element to the transmission element that is positioned depending on the shifting position and an accommodating segment that is disposed in the adjoining chamber; and
(b) determining a position of a transducer element that is dependent on the shifting position or a displacement of a transducer element that is dependent on a change of the shifting position by way of a detection device in order to detect the shifting position of the vehicle transmission, wherein the transducer element is mounted on the accommodating segment of the bar element.
The method can advantageously be implemented in combination with or using a version of the aforementioned sensor device. As a result of implementing the method, a shifting position of a vehicle transmission can advantageously be detected by way of a version of the aforementioned sensor device.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.